QWebEngine - how to disable Chrome sandbox using Quicknanobrowser (Qt5.4.1)

I have ported Qt5.4.1 to ARM platform, QtWebEgnine Quicknanobrowser is basic working fine but I have video player issue. In order to debug ffmpeg related video player issue, seems I have to disable sandbox to enable ffmpeg debug log to print out. For chrome browser, there is command line option '-no-sandbox' to disable sandbox, but this command line option is not working for Quicknanobrowser.

AFAIK there is no way to do this in Qt 5.4.1
I'm also waiting for an option to pass command line parameters to be able to set a proxy - that's the only way to set proxy in Blink (and I'm afraid we'll have to forget about proxyForUrl - not a big deal but... Webkit could be removed after 5.6 so we'll have to stick to old versions...)

According to this section "Updated Qt WebEngine and Qt WebView"
they are working on settings "Qt WebEngine now provides APIs for ... as well as settings"
Honestly I don't know if that includes command line parameters/settings...
BTW Still no binaries so you'll have to build it yourself or wait for beta
HTH